I have a 50 gallon tank with 2 systems of 2 T5 bulbs. My hammer coral has been shrinking. I haven't changed my light bulbs in about 5 months. Could that be why? Also, the hammer coral is under the same lighting system as an elegance coral. Should I move the elegance coral under one system with lower lighting or would it be better under the higher lighting one with the hammer coral?

I think some more info will aid everyone in helping you. How long have you had the coral? What are your water parameters- temp., PH, Alk, Ca, ammonia/nitrite, nitrate, etc? Do you do PWC's? If so how much and often?

What lighting was the Euphyllia ancora (Hammer coral) under in the store? You state 2 systems, so 4 bulbs setup on a single 50g, correct? What are the wattages and what type of bulbs are they (Aquasun, Blue Plus, True Actinic, etc)? What fish, if any are in the tank and if so, notice any signs of nipping at the polyps? What other corals are in the display? Is the coral receiving enough water flow (they dislike direct current)? Do you dose any chemicals: Ca, Alk, Iodine, etc?

Why do you want to move your Catalaphyllia jardinei (Elegance coral)? Is it exhibitting signs of regression?

I don't dose any chemicals. I have a yellow hawaiian tang, a false percula, firefish, flame angel and watchman goby. I do have 4 bulbs, 2 are only 18 watts and the other 2 are 24 watts. I have an elegance coral in the display also. The 18 watt bulbs are a coral life blue actinic 03 and the other is called a daylight bulb. The 24 watt bulbs are glo life power glow and life glow. I'm not sure if it is recieving enough current. Its about 10" away from and 20-22" under the output of my filter.

Ok, here's the rub. The Power Glow and Life Glow are Hagen brand and T8 bulbs. They are full sun spectrum according to a website, almost 10k. T8's are smack dab between intensities of VHO and T5 bulbs. Personally, I don't think you have enough light for the E. ancora; however, most aquarists I've seen/talked to keep their light 4-6" off the water's surface. Do you have individual reflectors for each bulb or are they installed under a single reflector? When you say shrinking, are the polyps visually getting smaller and not extending as much? What coloration are the polyps (losing their hue?)?

Hmm, quite odd because the only information available on Power Glow and Glow Life bulbs state they are T-8's. What unit did you purchase, maybe that will clear things up? Light fixtures with T5's should have individual parabolic reflectors; otherwise, 2 bulbs sharing a reflector are lowering each bulbs performance %.

How often are you doing PWC`s? I`m thinking that light might be playing a part here also. Another thing that could be happening also is the flame angel. They are not always reef safe. Mine destroyed a hammer coral after being good for 4 yrs. I would keep an eye on him to make sure he is not the culprit.

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